TX-28LB1P, TX-28LB1S - Panasonic TV Service Manual (repair manual)

tx-28lb1p, tx-28lb1s service manual
Model
TX-28LB1P TX-28LB1S
Pages
22
Size
2.66 MB
Type
PDF
Document
Service Manual
Brand
Device
TV / COLOUR TELEVISION
File
tx-28lb1p-tx-28lb1s.pdf
Date

Read Panasonic TX-28LB1P / TX-28LB1S Service Manual online

Colour Television
                   TX-28LB1P 
TX-28LB1P/S
Z8 Chassis
SPECIFICATION
Power Source:
220-240V a.c., 50Hz
Power Consumption:
66W
Stand-by Power
Consumption:
0,9W 
Aerial Impedance:
75
W unbalanced, Coaxial Type
Receiving System:
PAL B/G, PAL D/K ,PAL-60
SECAM B/G, SECAM D/K
M.NTSC (AV)
NTSC (AV only)
Receiving Channels:
VHF E2-E12
VHF H1-H2 (ITALY)
VHF A-H (ITALY)
VHF R1-R2
VHF R3-R5
VHF R6-R12
UHF E21-E69
CATV (S01-S05)
CATV S1-S10 (M1-M10)
CATV S11-S20 (U1-U10)
CATV S21-S41 (HYPERBAND)
Intermediate Frequency:
Video/Audio
Video
38,9MHz
Audio
32,4MHz, 
32,66MHz (A2 CZECH)
33,05MHz  (NICAM)
33,4MHz, 33,16MHz (A2)
33,05MHz (NICAM B/G)
Colour
34,47MHz 
34,5MHz, 34,65MHz 
Terminals:
AV1 IN
Video(21 pin) 1V p-p  75
W
Audio(21 pin) 500mV rms 10k
W
RGB (21 pin) 0,7V p-p 75
W
AV1 OUT
Video (21 pin) 1V p-p  75
W
Audio (21 pin) 500mV rms 1k
W
RCA IN
Video 1V p-p 75
W
RCA IN
Audio 500mV rms 10k
W
High Voltage:
25,5kV ± 1kV 
Picture Tube:
A66EHJ13X38 66cm
Audio Output:
2 x 10W (M.P.O.)
2 x  5W  (R.M.S.)
8
W Impedance
Headphones:
8
W Impedance
3,5mm
Accessories 
supplied :
Remote Control
2 x R6 (UM3) Batteries
Dimensions:
Height:
578mm
Width:
810mm
Depth:
468mm
Net weight:
31kg
Specifications are subject to change without notice.
Weights and dimensions shown are approximate.
NOTE:    This Service Manual should be used in
conjunction with the Z8 Technical guide.
ORDER No. 02-SM-024
CONTENTS
SAFETY PRECAUTIONS ......................................................................................................................................................... 2
SERVICE HINTS....................................................................................................................................................................... 3
ADJUSTMENT PROCEDURE AND FACTORY SETTINGS..................................................................................................... 4
WAVEFORM PATTERN TABLE ............................................................................................................................................... 5
ALIGNMENT SETTINGS .......................................................................................................................................................... 6
BLOCK DIAGRAMS.................................................................................................................................................................. 7
PARTS LOCATION................................................................................................................................................................. 10
REPLACEMENT PARTS LIST................................................................................................................................................ 11
SCHEMATIC DIAGRAMS....................................................................................................................................................... 17
CONDUCTOR VIEWS ............................................................................................................................................................ 20
SAFETY PRECAUTIONS
GENERAL GUIDE LINES
1.  It is advisable to insert an isolation transformer in the
a.c. supply before servicing a hot chassis.
2.  When servicing, observe the original lead dress in the
high voltage circuits. If a short circuit is found, replace
all parts that have been overheated or damaged by
the short circuit.
3.  After servicing, see that all the protective devices
such as insulation barriers, insulation papers, shields
and isolation R-C combinations are correctly
installed.
4.  When the receiver is not being used for a long period
of time, unplug the power cord from the a.c. outlet.
5.  Potentials as high as 26,5kV are present when this
receiver is in operation. Operation of the receiver
without the rear cover involves the danger of a shock
hazard from the receiver power supply. Servicing
should not be attempted by anyone who is not
familiar with the precautions necessary when working
on high voltage equipment. Always discharge the
anode of the tube.
6.  After servicing make the following leakage current
checks to prevent the customer from being exposed
to shock hazard.
LEAKAGE CURRENT COLD CHECK
1.  Unplug the a.c. cord and connect a jumper between
the two prongs of the plug.
2.  Turn on the receiver’s power switch.
3.  Measure the resistance value with an ohmmeter,
between the jumpered a.c. plug and each exposed
metallic cabinet part on the receiver, such as screw
heads, aerials, connectors, control shafts etc. When
the exposed metallic part has a return path to the
chassis, the reading should be between 4M ohm and
20M ohm. When the exposed metal does not have a
return path to the chassis, the reading must be
infinite.
LEAKAGE CURRENT HOT CHECK
1.  Plug the a.c. cord directly into the a.c. outlet. Do not
use an isolation transformer for this check.
2.  Connect a 2k
W 10W resistor in series with an
exposed metallic part on the receiver and an earth,
such as a water pipe.
3.  Use an a.c. voltmeter with high impedance to
measure the potential across the resistor.
4.  Check each exposed metallic part and check the
voltage at each point.
5.  Reverse the a.c. plug at the outlet and repeat each of
the above measurements.
6.  The potential at any point should not exceed
1,4Vrms. In case a measurement is outside the limits
specified, there is a possibility of a shock hazard, and
the receiver should be repaired and rechecked before
it is returned to the customer.
X-RADIATION WARNING
1.  The potential sources of X-Radiation in TV sets are
the high voltage section and the picture tube.
2.  When using a picture tube test jig for service, ensure
that the jig is capable of handling 26,5kV without
causing X-Radiation.
NOTE:
 It is important to use an accurate periodically
calibrated high voltage meter.
1.  Set the brightness to minimum.
2.  Measure the high voltage. The meter should indicate.
25,5 kV    ± 1kV.
If the meter indication is out of tolerance, immediate
service and correction is required to prevent the
possibility of premature component failure.
3.  To prevent any X-Radiation possibility, it is essential
to use the specified tube.
HOT CHECK CIRCUIT
a.c. VOLTMETER
WATER PIPE
(EARTH)
TO INSTRUMENT'S EXPOSED
METALLIC PARTS
Fig. 1.
2k
W 10 Watts
2
SERVICE HINTS
How to remove the rear cover
1.  Remove the 6 screws as shown in 
Fig.2.
LOCATION OF CONTROLS
3
Screws
 Fig.2.
Focus
E - Board
Y - Board
Screen
Fig.3.
ADJUSTMENT PROCEDURE
Item/Preparation
   Adjustments
    Confirm the following voltages.
TPE1
3,3
± 0,3V
TPE13 -13
± 1V
TPE2
200
± 10V
TPE14 27,5
± 1,5V
TPE3
13,25 ± 1V
TPE15 28
± 1,5V
TPE4
10,5
± 1V
TPE16 11,5
± 1V
TPE8
5
± 0,3V
TPE17 8
± 1V
TPE11 147
± 10V
TPE18 5
± 0,3V
+B SET-UP
1.  Receive a Greyscale signal.
2.  Set the controls:
Brightness
Minimum
Contrast
Minimum
Volume
Minimum
Cut-Off / Ug2 Adjustment
1.  Receive a Greyscale signal.
2.  Degauss the tube externally.
3.  Set the TV into Service Mode 1.
4.  Select Ug2 Test.
Set Contrast on maximum, set Brightness on centre, switch
on AV mode.
Enter Service mode. Set Sub-Brightness to 31. Select
Ug2.Press "+" and adjust screen Vr till sharp vertical line is
visible and LED switches off. Then reduce screen Vr till LED
is just switched on (pin6 of connector E1 must be connected
to GND).
Note: To set up ”white balance” first set up “Cut off” register to 8. Then set up “high-light” with the help of “drive” registers.
Finish setting-up of “Low-light” with the help of  ”Cut-off” register. Carry out setting-up of  ”white balance” in available TV
systems (PAL, SECAM).
FACTORY SETTINGS
To return customer settings to factory settings and clear owner ID of all information input by the customer, enter Self-Check
mode. Press the down (-/v) button on the customer controls at the front of the TV set, at the same time pressing the STATUS
button
on the remote control. To exit Self Check, switch off the TV set at the power button.
Service Aids
To aid in the service of our current chassis there are a number of Service Aids which have been made available.
· 
LUCI
 interface kit (Linked Utility Computer Interface)
Part number: TZS6EZ002
This contains interface and cables for connecting TV service connector and a PC as well as diagnostic software. As new
models are introduced upgrade software will become available.
· 
VICI
 (Visual Interactive Computer Information)
These C.D.'s contain multimedia documentation providing quick access to service information.
Part No. TZS7EZ006, TZS7EZ005, TZS8EZ001& TZS9EZ001
1. Service Manuals
2. Instruction Books
3. Technical Information
· 
TASMIN
 (Technically Advanced System for Multimedia Interactive Notes)
As well as providing a first step towards more interactive training this product also achieves quick access to Technical
Information.
4
NOTE: Self Check should only be used when refurbishing the TV set and not during normal repair work.
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Here you can read online and download Panasonic TX-28LB1P / TX-28LB1S Service Manual in PDF. TX-28LB1P / TX-28LB1S service manual will guide through the process and help you recover, restore, fix, disassemble and repair Panasonic TX-28LB1P / TX-28LB1S TV. Information contained in service manuals typically includes schematics / circuit diagrams, wiring diagrams, block diagrams, printed wiring boards, exploded views, parts list, disassembly / assembly, pcb.